1. Field of the Invention
The present invention relates to a method of feeding sheets, and more specifically to a method of feeding sheets to a desired position by making use of a vacuum suction pad.
2. Description of the Related Art
There is known a mechanism for attracting and holding the uppermost sheet of a stack of sheets by a suction pad to thereby feed the same. This type of mechanism comprises a suction pad for attracting and holding the uppermost sheet of the stacked sheets, and a suction-pad displacing mechanism for detaching or displacing the suction pad from the sheets, and a vacuum suction source for supplying vacuum to the inside of the suction pad.
More specifically, the displacing mechanism is energized to displace the suction pad from the sheets by a predetermined stroke. After the suction pad is pressed against the sheets, the vacuum suction source is energized to subject the inside of the suction pad to the vacuum, thereby attracting the uppermost sheet under such a vacuum by the suction pad and feeding the same.
However, in the above-described prior art, the suction pad is normally displaced by a certain stroke from the sheets without taking into consideration any remaining stacked sheets. Therefore, when the suction pad is pressed against the sheets, it releases air from in-between the stacked sheets. As a result, a plurality of sheets are sucked simultaneously by the suction pad, thereby malfunctioning with the succeeding sheet feeding operation in a sheet feeding apparatus.